Long Sleeping '79 CBX Restoration

[shiskowd]

Assuming they are extra harsh chemicals in the primer is the reason why they won't sell in Canada or is it just not a big enough market?

I believe the issue in Canada is the propellant used in the aerosols. Couple of years back some regulation changed and manufactures aren't willing or can't make the formulation work for the small market that Canada is.

Sorry for your paint troubles. I've painted several whole cases and many valve covers and other engine parts with Dupli-color paint. Never used primer and they all look good up to 10-12 years later. Just strip and clean everything again and paint it. Don't agonize over the valve cover either, just paint it. They were painted the same as the rest of the engine from the factory.

I certainly had the the cases fully stripped/clean - good to know it lasts. I'll paint the valve cover also...

[shiskowd]

I settled on using the the frame for the 'B' bike and therefore the engine case from the same bike. Cylinders and head will be from the 'A' bike. I'll compare all the internal case components and choose those that have the least wear.

I plastigauged all the bearing and rod journals on the crank. The acceptable wear limit is 0.08mm for all crank bearings and most of the crank to case bearing clearances are just under (~0.07mm). The rod bearings were slightly looser, some over the wear limit. I'll be investing in a full set of bearings . The good news is the wear was even, no deep scoring on the crank journals, just some very light grooves that should polish out easily.

I don't' have the means to accurately check the run out, spec is just 0.002" (0.05mm). I can't see how it would be out of spec with the bearings wearing this evenly.



Took apart the oil pumps from both engines, cleaned in the parts washer and the ultra sonic cleaner. Both pumps show very little wear, all well within the specs in the service manual. I'll need a new pickup screen, the rubber is very brittle and will surely break if I try to stretch over the intake housing.

Is there much else to the pump to be concerned?

[steve murdoch icoa #5322]

A couple years ago i could not get a screen from Honda.
They may be available from some of the North American vendors but i got one from SixCenter.
https://www.sixcenter.nl/onderdelen/det ... ?aid=99358

[NobleHops]

See Terry Schmitt for these oil pump screens, aka tevan here on this site.

[shiskowd]

See Terry Schmitt for these oil pump screens, aka tevan here on this site.

Terry & I have exchanged email about his hose service and screens - thanks.

Took apart both clutches. Both clutch baskets look good, the A bike clutch has less wear on the one edge of the basket fingers. Both sets of clutchplates are well within spec.


On to the ignition bits. The advancer (part #422)mechanism moves freely with some light lubricant.


Is there any salvaging these pulsers/igniters? I've seen posts where you can clean them up and pour some epoxy over the leaky parts to extend their life. These things leaked a fair amount resting in a box in my garage over the summer. I think I may spring for a Dyna or Sachse ignition.

[shiskowd]

Working my way though 1 set of carbs with the help of Mike Nixon's book. I have the first 3 carbs completely stripped, didn't manage to bugger anything up including removal of the pilot jet. One question - the rubber plug with a spring behind it under the air cut valve diaphragm - how does one remove that to get a thorough cleaning?

[daves79x]

DO NOT try to remove it! Everything will be fine with it staying in place.

Dave

[shiskowd]

DO NOT try to remove it! Everything will be fine with it staying in place.

Dave

Go it! I won't ask why!

The number 4 carb has all the throttle/choke linkages and what not. Mike doesn't take these off in his carb manual (no mention), mine are beyond filthy and would be easier to clean with them separated. Should be able to piece it back together, right?!

[steve murdoch icoa #5322]

There are a couple very helpful videos on the Mike Nixon website in regards to the carb rebuild.
Even one about the choke springs.
https://www.motorcycleproject.com/text/tech_videos.html

[daves79x]

Remove the bell crank and associated hardware and bracket, but do not remove any of the fast idle linkage. You likely found that you also need new joint rubbers?

Dave

[shiskowd]

Remove the bell crank and associated hardware and bracket, but do not remove any of the fast idle linkage. You likely found that you also need new joint rubbers?

Thanks Dave - took it down to the fast idle linkage (I can see how at full chock it will nudge open the throttles). Most all the rubber bits are needing replacement including the rubber over the ball joints.



Stripped all the parts of the carbs and sorted.



I invested in a set of JIS philips screwdrivers and bits for a 1/4" impact driver to take out all the various screws. Even so, I had to cut grooves in several with a Dremel to use a large flat blade driver. For the jets I sharpened up a couple flat blade screwdrivers so they fit tight into the jet bodies and the primary main tube which all removed cleanly. The suggested #4NC40 tap and screw made short work of the buried idle jet.

However, the very last jet I tried to remove was a problem. The last idle mixture (pilot) screw is proved to be frozen in place. I heated the casted with a small butane torch - still no go and ended up searing off the top of the screw. I then used the Dremel to cut another groove, sacrificing a bit of the casting but still won't move. I cleaned up the top of the broken screw to get a clean center punch mark to drill it out but I thought I would see what guidance from the experts here who have no doubt seen this before.



Further, when I was prying the gasket out of one of the float bowels I somehow managed to break the overflow standpipe I've seen a few threads on other sites how to replace these, doesn't seem to difficult as they're pressed in but where does one find this little brass tube?



Thanks in advance for your help!!

[daves79x]

You can successfully drill out the pilot screw, clean up the threads with a tap and make sure you punch out the tip of the old one. You can find matching brass tubing at hobby stores, or these days, very likely on-line.

Dave

[shiskowd]

I got the pilot screw out with a 2nd set of hands holding a small butane torch on it while I turned it out. The aluminum casting carries the heat away too quickly to work it solo.

Next up was the various brake system components. I have to say, this was by far the most difficult pieces to disassemble and clean up in my restoration journey thus far. Brake fluid sitting idle for 20+ years makes quite the mess.







I applied a 50/50 mixture of acetone and ATF to free up the corroded pieces. The pistons took significant effort to work out of the calipers and every screw in both master cylinders had to be extracted/destroyed in some fashion to get them out.



Lots of cleanup and painting needed yet!

[daves79x]

Inspect both master cylinder bores for pitting. If present, you're just chasing your tail trying to rebuild them. Look for good replacements or get reproductions (front).

Dave

[wyly]

Ignore this brake advice if you're only after oem brake setup.

I went to OMS in Ogden industrial and bought a complete brake set from either a 83 or 84 CB750f, simple swap. Money well spent, when combined with SS brake lines significantly improved braking. Unless you run into another CBX owner no one will notice they're not original.